This paper reports that a charge-transfer salt dibutylammonium bis-7,7,8,8-tetraeyanoquinodimethane [DBA （TCNQ）2] has been prepared. The temperature dependences of the DC electrical conductivity of the DBA （TCNQ）2...This paper reports that a charge-transfer salt dibutylammonium bis-7,7,8,8-tetraeyanoquinodimethane [DBA （TCNQ）2] has been prepared. The temperature dependences of the DC electrical conductivity of the DBA （TCNQ）2 single crystal measured along the crystallographic a, b, and c axes are reported. The crystal shows semicondueting behaviour and the room-temperature conductivities are highly anisotropic （σa = 3.63× 10^-4S/cm, σb = 2.84× 10^-6S/cm, and （σe = 1.82 × 10^-5S/cm）. Particularly, a sharp semiconductor to semiconductor transition has been observed around 270 K on the resistivity curves measured under cooling and heating. In addition, thermal hysteresis phenomena on conductivity and differential scanning calorimetry curves are also reported.展开更多
The present paper contains the effects of the ammonium ion, counter ion, solvent and anion being transferred on the solid-liquid phase transfer equilibrium constant of quaternary ammonium salts. The most striking diff...The present paper contains the effects of the ammonium ion, counter ion, solvent and anion being transferred on the solid-liquid phase transfer equilibrium constant of quaternary ammonium salts. The most striking difference between solid-liquid and liquid-liquid phase transfer equilibriums is that the length of alkyl chain shows a large effect on the latter but little on the former This means that the chain length affects only the hydrophobicity, rather than the lipophilicity.Keywords Quaternary ammonium salt, Phase transfer catalysis, Equilibrium constant, Hydrophobicity, Lipophilicity展开更多
In this study was to investigate, by phase-transfer catalysis, the activity of single and mixed ammonium and phosphonium salts grafted on a 揼el-type?styrene-7% divinylbenzene copolymer in the oxidation of benzyl alco...In this study was to investigate, by phase-transfer catalysis, the activity of single and mixed ammonium and phosphonium salts grafted on a 揼el-type?styrene-7% divinylbenzene copolymer in the oxidation of benzyl alcohol with hydrogen peroxide. A wide variety of catalysts with different quaternary groups and different quaternary chain length substituents were examined. The activity of single 搊nium?salts increases as a consequence of the association of ammonium and phosphonium salts grafted on the same polymeric support. The activity of polymer-supported ammonium and phosphonium salts increases with the number of carbon atoms contained in the alkyl radicals of the onium and of the functionalization degree with phosphonium groups.展开更多
The photosensitive initiating system composed of 7-diethylamino-3-(2'-benzimidazolyl)coumarin dye (DEDC) and diphenyliodonium hexafluorophosphate (DIHP) which act as the sensitizer and the initiator respectively, ...The photosensitive initiating system composed of 7-diethylamino-3-(2'-benzimidazolyl)coumarin dye (DEDC) and diphenyliodonium hexafluorophosphate (DIHP) which act as the sensitizer and the initiator respectively, can be used to initiate the polymerization of methyl methacrylate (MMA). The results showed that when exposed to visible light, coumarin dye/iodonium salt undergoes quick electron transfer from DEDC to DIHP and free radicals are produced. The visible light photoinduced reaction between DEDC and DIHP is mainly through the excited singlet state of DEDC and thus it is a little sensitive to O-2. The influence of concentration of DEDC, DIHP and MMA on the rate of photopolymerization of MMA was also investigated.展开更多
High level density functional theory (DFT) calculations are performed for the first time to answer the question whether the arginine-carboxylate salt bridge stays in a zwitterionic state or a neutral one. The results ...High level density functional theory (DFT) calculations are performed for the first time to answer the question whether the arginine-carboxylate salt bridge stays in a zwitterionic state or a neutral one. The results indicate that in the gas phase, the neutral form is more stable and hence proton transfer occurs from guanidinium to carboxylate. However, in an aqueous solution the zwitterionic form should be favored. The difference might he caused by the electrostatic interaction between the salt bridge and its molecular environment. Therefore, the solvation effect has to be considered in the modeling of proteins, whose stabilization depends heavily on the salt-bridges.展开更多
The exothermic chemical reaction of CaCl2 (calcium chloride) with NH3 (ammonia) can be utilized as an energy storage system. Since this reaction is a typical gas-solid reaction, the reaction rate is controlled by the ...The exothermic chemical reaction of CaCl2 (calcium chloride) with NH3 (ammonia) can be utilized as an energy storage system. Since this reaction is a typical gas-solid reaction, the reaction rate is controlled by the heat transfer rate. In order to improve the low heat transfer rate of the ammoniation and the deammoniation of CaCl2, the influence of a heat transfer media (Ti: titanium) on the heat transfer rate of the solid ammoniated salt (CaCl2.mNH3) was studied and tested experimentally. The performance tests were carried out under the conditions of various weight ratios of Ti. No decrease of the activation of chemical reaction and no corrosion of experimental apparatus were observed on the repeated runs (≥30 times each). The heat transfer rate of ammoniated salt was greatly improved by adding Ti under the constant pressure (0.5 MPa). The reaction time required for the ammoniation of CaCl2 mixed with Ti was approximately 16% - 54% shorter than that of CaCl2 alone, and the reaction time required for the deammoniation was also approximately 19% - 59% shorter than that of CaCl2 alone.展开更多
Using 4-Dialkylaminopyridinium salt as a thermal stable phase-transfer catalyst (PTC), the excellent results were obtained in the halogen-exchange fluorination.
Here we report an in situ assembly growth method that controls the growth of NiTCNQ on the surface of graphdiyne(GDY).The catalytic system of donor–acceptor–donor(GDY/TCNQ/Ni)structure with multiple charge transfer(...Here we report an in situ assembly growth method that controls the growth of NiTCNQ on the surface of graphdiyne(GDY).The catalytic system of donor–acceptor–donor(GDY/TCNQ/Ni)structure with multiple charge transfer(CT)was achieved by controlling the growth of NiTCNQ on the surface of GDY.Significantly,a controlled double layer interface of GDY/TCNQ/Ni was formed.This system implemented simultaneously the two elements we expected(1)an incomplete CT,and(2)the infinite distribution of active sites originating from highly asymmetric surface charge distribution.The high conductivity and typical semiconductor characteristics of the catalyst endows it with high catalytic activity.We found that an electrolytic cell consisting of the CT salt as a catalyst provided a 1.40 V ultra-small cell voltage up to 10 mA cm−2 and the outer GDY film effectively prevented the corrosion of the catalyst.Our study is the first to introduce CT complexes to a novel catalytic material platform for high selectivity of catalysts,and undoubtedly demonstrates the high selectivity,stability,and activity of such catalytic systems,which provides a new space for the development of novel conceptual catalysts.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No 10604038)the Program for New Century Excellent Talents in University (NCET-2007)
文摘This paper reports that a charge-transfer salt dibutylammonium bis-7,7,8,8-tetraeyanoquinodimethane [DBA （TCNQ）2] has been prepared. The temperature dependences of the DC electrical conductivity of the DBA （TCNQ）2 single crystal measured along the crystallographic a, b, and c axes are reported. The crystal shows semicondueting behaviour and the room-temperature conductivities are highly anisotropic （σa = 3.63× 10^-4S/cm, σb = 2.84× 10^-6S/cm, and （σe = 1.82 × 10^-5S/cm）. Particularly, a sharp semiconductor to semiconductor transition has been observed around 270 K on the resistivity curves measured under cooling and heating. In addition, thermal hysteresis phenomena on conductivity and differential scanning calorimetry curves are also reported.
文摘The present paper contains the effects of the ammonium ion, counter ion, solvent and anion being transferred on the solid-liquid phase transfer equilibrium constant of quaternary ammonium salts. The most striking difference between solid-liquid and liquid-liquid phase transfer equilibriums is that the length of alkyl chain shows a large effect on the latter but little on the former This means that the chain length affects only the hydrophobicity, rather than the lipophilicity.Keywords Quaternary ammonium salt, Phase transfer catalysis, Equilibrium constant, Hydrophobicity, Lipophilicity
文摘In this study was to investigate, by phase-transfer catalysis, the activity of single and mixed ammonium and phosphonium salts grafted on a 揼el-type?styrene-7% divinylbenzene copolymer in the oxidation of benzyl alcohol with hydrogen peroxide. A wide variety of catalysts with different quaternary groups and different quaternary chain length substituents were examined. The activity of single 搊nium?salts increases as a consequence of the association of ammonium and phosphonium salts grafted on the same polymeric support. The activity of polymer-supported ammonium and phosphonium salts increases with the number of carbon atoms contained in the alkyl radicals of the onium and of the functionalization degree with phosphonium groups.
基金This work was supported by the National Natural Science Foundation of China (No. 59773011).
文摘The photosensitive initiating system composed of 7-diethylamino-3-(2'-benzimidazolyl)coumarin dye (DEDC) and diphenyliodonium hexafluorophosphate (DIHP) which act as the sensitizer and the initiator respectively, can be used to initiate the polymerization of methyl methacrylate (MMA). The results showed that when exposed to visible light, coumarin dye/iodonium salt undergoes quick electron transfer from DEDC to DIHP and free radicals are produced. The visible light photoinduced reaction between DEDC and DIHP is mainly through the excited singlet state of DEDC and thus it is a little sensitive to O-2. The influence of concentration of DEDC, DIHP and MMA on the rate of photopolymerization of MMA was also investigated.
文摘High level density functional theory (DFT) calculations are performed for the first time to answer the question whether the arginine-carboxylate salt bridge stays in a zwitterionic state or a neutral one. The results indicate that in the gas phase, the neutral form is more stable and hence proton transfer occurs from guanidinium to carboxylate. However, in an aqueous solution the zwitterionic form should be favored. The difference might he caused by the electrostatic interaction between the salt bridge and its molecular environment. Therefore, the solvation effect has to be considered in the modeling of proteins, whose stabilization depends heavily on the salt-bridges.
文摘The exothermic chemical reaction of CaCl2 (calcium chloride) with NH3 (ammonia) can be utilized as an energy storage system. Since this reaction is a typical gas-solid reaction, the reaction rate is controlled by the heat transfer rate. In order to improve the low heat transfer rate of the ammoniation and the deammoniation of CaCl2, the influence of a heat transfer media (Ti: titanium) on the heat transfer rate of the solid ammoniated salt (CaCl2.mNH3) was studied and tested experimentally. The performance tests were carried out under the conditions of various weight ratios of Ti. No decrease of the activation of chemical reaction and no corrosion of experimental apparatus were observed on the repeated runs (≥30 times each). The heat transfer rate of ammoniated salt was greatly improved by adding Ti under the constant pressure (0.5 MPa). The reaction time required for the ammoniation of CaCl2 mixed with Ti was approximately 16% - 54% shorter than that of CaCl2 alone, and the reaction time required for the deammoniation was also approximately 19% - 59% shorter than that of CaCl2 alone.
基金the Natural Science Foundation of Zhejiang Province (No. 299024).
文摘Using 4-Dialkylaminopyridinium salt as a thermal stable phase-transfer catalyst (PTC), the excellent results were obtained in the halogen-exchange fluorination.
基金by a generous grant from the National Key Research and Development Project of China(no.2018YFA0703501)the National Nature Science Foundation of China(nos.21790050,21790051,and 22021002)the Key Program of the Chinese Academy of Sciences(no.XDPB13).
文摘Here we report an in situ assembly growth method that controls the growth of NiTCNQ on the surface of graphdiyne(GDY).The catalytic system of donor–acceptor–donor(GDY/TCNQ/Ni)structure with multiple charge transfer(CT)was achieved by controlling the growth of NiTCNQ on the surface of GDY.Significantly,a controlled double layer interface of GDY/TCNQ/Ni was formed.This system implemented simultaneously the two elements we expected(1)an incomplete CT,and(2)the infinite distribution of active sites originating from highly asymmetric surface charge distribution.The high conductivity and typical semiconductor characteristics of the catalyst endows it with high catalytic activity.We found that an electrolytic cell consisting of the CT salt as a catalyst provided a 1.40 V ultra-small cell voltage up to 10 mA cm−2 and the outer GDY film effectively prevented the corrosion of the catalyst.Our study is the first to introduce CT complexes to a novel catalytic material platform for high selectivity of catalysts,and undoubtedly demonstrates the high selectivity,stability,and activity of such catalytic systems,which provides a new space for the development of novel conceptual catalysts.
